Selective MT2 melatonin receptor antagonists block melatonin‐mediated phase advances of circadian rhythms

@article{Dubocovich1998SelectiveMM,
  title={Selective MT2 melatonin receptor antagonists block melatonin‐mediated phase advances of circadian rhythms},
  author={Margarita L Dubocovich and Kenneth Yun and Walid M. Al-Ghoul and Susan Benloucif and Monica I. Masana},
  journal={The FASEB Journal},
  year={1998},
  volume={12},
  pages={1211 - 1220}
}
This study demonstrates the involvement of the MT2 (Mel1b) melatonin receptor in mediating phase advances of circadian activity rhythms by melatonin. In situ hybridization histochemistry with digoxigenin‐labeled oligonucleotide probes revealed for the first time the expression of mt1 and MT2 melatonin receptor mRNA within the suprachiasmatic nucleus of the C3H/HeN mouse. Melatonin (0.9 to 30 μg/mouse, s.c.) administration during 3 days at the end of the subjective day (CT 10) to C3H/HeN mice… 
Effect of MT1 melatonin receptor deletion on melatonin‐mediated phase shift of circadian rhythms in the C57BL/6 mouse
TLDR
It is suggested that melatonin‐mediated phase advances of circadian rhythms of neuronal firing in the SCN in vitro may involve activation of the MT2 receptor while in vivo activation ofThe MT1 and possibly theMT2 receptor may be necessary for the expression of melatonin-mediated phase shifts of overt circadian activity rhythms.
Circadian rhythm of mt1 melatonin receptor expression in the suprachiasmatic nucleus of the C3H/HeN mouse 1
TLDR
Results suggest that mt1 melatonin receptor rhythm in the C3H/HeN mouse SCN is regulated both by light and by the biological clock as distinct rhythms of both mRNA and protein are differentially expressed under a LD cycle and constant dark conditions.
Melatonin desensitizes endogenous MT2 melatonin receptors in the rat suprachiasmatic nucleus: relevance for defining the periods of sensitivity of the mammalian circadian clock to melatonin
TLDR
In vivo the nightly secretion of melatonin desensitizes endogenous MT2 melatonin receptors in the mammalian SCN thereby providing a temporally integrated profile of sensitivity of the mammalian biological clock to a melatonin signal.
The Endogenous Melatonin (MT) Signal Facilitates Reentrainment of the Circadian System to Light-Induced Phase Advances by Acting Upon MT2 Receptors
TLDR
The data suggest the endogenous melatonin signal facilitates reentrainment of the circadian system to phase advances on the level of the SCN molecular clockwork by acting upon MT2 receptors.
Activation of MT(2) melatonin receptors in rat suprachiasmatic nucleus phase advances the circadian clock.
TLDR
It is concluded that melatonin mediates phase advances of the SCN circadian clock at both dusk and dawn via activation of MT(2) melatonin receptor signaling.
Circadian Pattern of Melatonin MT1 and MT2 Receptor Localization in the Rat Suprachiasmatic Nucleus
TLDR
It is found that melatonin receptor MT1 density and distribution varies with circadian time, which creates a time window during which melatonin can affect the operation of the SCN.
MT1 and MT2 Melatonin Receptors: A Therapeutic Perspective.
TLDR
The pharmacological properties of a slow-release melatonin preparation and synthetic ligands are described, with emphasis on identifying specific therapeutic effects mediated through MT1 and MT2 receptor activation.
Molecular pharmacology, regulation and function of mammalian melatonin receptors.
TLDR
An accurate characterization of melatonin receptors mediating specific functions in native tissues can only be made using receptor specific ligands, with the understanding that receptor ligands may change efficacy in both native tissues and heterologous expression systems.
Functional MT1 and MT2 melatonin receptors in mammals
TLDR
The melatonin-mediated responses elicited by activation of MT1 and MT2 native melatonin receptors are dependent on circadian time, duration and mode of exposure to endogenous or exogenous melatonin, and functional receptor sensitivity.
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